PQI Question

Besmer, Brad Brad.Besmer at lsi.com
Thu Oct 31 16:29:51 PDT 2013

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Your question could be interpreted 2 ways, so I will try to explain what you
would need.
A SGL needs to start with one of the SGL descriptors (Data Block, Bit Bucket,
Standard SGL Segment, Last Standard SGL Segment or Last Alternative SGL
Segment Descriptor). It cannot immediately start off with the Alternative SGL
Segment (Table A.2) itself.
So, for example, for a SOP Command IU, the Data Buffer Descriptor Area starts
at offset 64. At this location, a 16-byte Last Alternative SGL Segment
descriptor (Table A.1), which itself is effectively a pointer to the
Alternative SGL Segment (Table A.2), which is a single array of Alternative
Data Block descriptors (Table A.3).
Clear as mud?
From: owner-t10 at t10.org [mailto:owner-t10 at t10.org] On Behalf Of Paul
Sent: Thursday, October 31, 2013 4:44 PM
To: t10 at t10.org
Subject: PQI Question
Marvell has a question about PQI.
Regarding Alternative SGL Segment in the PQI Spec, Annex A - Can the very
first segment be an Alternative SGL Segment?
Paul Wassenberg

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